U.S. patent application number 14/395481 was filed with the patent office on 2015-03-12 for method of removing oil sludge and recovering oil from oil sludge with nanoemulsion surfactant system.
The applicant listed for this patent is BCI CHEMICAL CORPORATION SDN. BHD.. Invention is credited to Yang Loong Chong, Ming Hoong Looi, Wasan Saphanuchart, Chun Hwa See.
Application Number | 20150068950 14/395481 |
Document ID | / |
Family ID | 49383787 |
Filed Date | 2015-03-12 |
United States Patent
Application |
20150068950 |
Kind Code |
A1 |
See; Chun Hwa ; et
al. |
March 12, 2015 |
Method of removing oil sludge and recovering oil from oil sludge
with nanoemulsion surfactant system
Abstract
A method of treating a first batch of oil sludge containing
entrapped oil residue comprises the steps comprises the steps of
bringing into contact the first batch of oil sludge to a liquid
composition of an emulsion with or without a carrier, wherein the
emulsion comprises an alkylpolyglucoside surfactant in 2 to 40% by
weight of total composition; a co-surfactant in 1 to 30% by weight
of total composition selected from the group consisting of C3 to
C18 alcohols, C3 to C18 alkyl lactates, lecithins, C3 to C18 fatty
acids and any mixtures thereof; an oil phase in 15 to 90% by weight
of total composition; and an aqueous phase in 0.5 to 20% by weight
of total composition; homogenizing the liquid composition with the
first batch of oil sludge; and fluidizing the oil sludge that the
oil residues are substantially dissociated from the solid object
forming a liquid phase including the liquid composition and the
separated oil.
Inventors: |
See; Chun Hwa; (Selangor,
MY) ; Saphanuchart; Wasan; (Selangor, MY) ;
Looi; Ming Hoong; (Selangor, MY) ; Chong; Yang
Loong; (Selangor, MY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BCI CHEMICAL CORPORATION SDN. BHD. |
Selangor |
|
MY |
|
|
Family ID: |
49383787 |
Appl. No.: |
14/395481 |
Filed: |
April 22, 2013 |
PCT Filed: |
April 22, 2013 |
PCT NO: |
PCT/MY13/00087 |
371 Date: |
October 18, 2014 |
Current U.S.
Class: |
208/13 |
Current CPC
Class: |
B01D 11/0288 20130101;
C10G 1/04 20130101; C09K 8/524 20130101; C10G 29/22 20130101 |
Class at
Publication: |
208/13 |
International
Class: |
C10G 29/22 20060101
C10G029/22 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 20, 2012 |
MY |
PI 2012700208 |
Claims
1. A method of treating a first batch of oil sludge containing
entrapped oil residue, comprising the steps of: bringing into
contact the first batch of oil sludge to a liquid composition of an
emulsion with or without a carrier, wherein the emulsion comprises
an alkylpolyglucoside surfactant in 2 to 40% by weight of total
composition, a co-surfactant in 1 to 30% by weight of total
composition selected from the group consisting of C3 to C18
alcohols, C3 to C18 alkyl lactates, lecithins, C3 to C18 fatty
acids and any mixtures thereof, an oil phase in the range of 15 to
90% by weight of the total composition, and an aqueous phase in the
range of 0.5 to 20% by weight of total composition; homogenizing
the liquid composition with the first batch of oil sludge; and
fluidizing the oil sludge, wherein the oil residues are
substantially dissociated from any solid objects so as to form a
liquid phase, wherein the liquid phase includes the liquid
composition and separated oil.
2. The method according to claim 1, further comprising the steps
of: recycling the liquid phase or a portion of the liquid phase to
a second batch of oil sludge, wherein the second batch of oil
sludge contains oil residues entrapped to the solid objects; and
homogenizing the liquid phase or the portion of the liquid phase to
the second batch of oil sludge to separate the oil residues from
the solid objects.
3. The method according to claim 1, further comprising the steps
of: continuously removing the separated solid objects from the
liquid phase; and optionally, adding a new volume of oil sludge
into the liquid phase.
4. The method according to claim 1, further comprising the step of
heating the liquid composition and the first batch of oil sludge
during the homogenizing step.
5. The method according to claim 1, wherein the emulsion has a
concentration in the range of 0.01 to 10% by weight of the total
liquid composition when the carrier is used.
6. The method according to claim 1, wherein the liquid composition
and the oil sludge are in a ratio in the range of 1-10:20 by weight
percentage.
7. The method according to claim 1, wherein the carrier is selected
from the group consisting of light crude oil, paraffin oil, diesel,
mineral oil, kerosene, glycols, liquid hydrocarbons with a
viscosity less than 5000 cps at 25.degree. C., water, salt water,
brine and combinations thereof.
8. The method according to claim 1, wherein the emulsion further
comprises a pour point depressant or wax inhibitors selected from
the group consisting of ethylene/alkene copolymers, ethylene/vinyl
acetate copolymers, ethylene acrylonitrile copolymers, acrylate
ester polymers, methacrylate ester polymers, maleic copolymers,
alkyl phenol-formaldehyde resins, hexatriethanolamine oleate
esters, polyolefins and combinations thereof present in an amount
of 5 to 40% by weight of the total composition.
9. The method according to claim 1, wherein the emulsion further
comprises a stabilizer selected from the group consisting of
dodecylbenzenesulfonic acid, arylalkanesulfonates, sulfosuccinate
esters, alkyldiphenylether sulfonates, alkyldiphenylether
disulfonates alkylnaphthalenesulfonates, naphthalenesulfonic
acid-formaldehyde condensates and combinations thereof present in
an amount of 1 to 10% by weight of the total composition.
10. The method according to claim 1, wherein the oil phase is
selected from the group consisting of terpenes, aromatic
hydrocarbons, glycols, esters, fatty acid ester, fatty ester,
glycol ethers, mineral oil, paraffin oil, plant-based oil, diesel,
petroleum distillates and combinations thereof.
11. The method according to claim 1, wherein the emulsion further
comprises an oxidizing biocide selected from the group consisting
of chlorine/hypochlorite or bromide/hypochlorite, hypochlorite
salts, hypobromite salts, stabilized bromine chloride, hydroxyl
radicals, chloramines, chlorine dioxide, chloroisocyanurates,
halogen-containing hydantoins, hydrogen peroxide, hydrogen
peracetic acid and combinations thereof present in the range of 1
to 5% by weight of the total composition.
12. The method according to claim 1, wherein the emulsion further
comprises a non-oxidizing biocide selected from the group
consisting of aldehyde biocides, quaternary phosphonium compounds,
quaternary ammonium surfactants, cationic polymers, organic
bromides, metronidazole, isothiazoles, isothiazolinones, thiones,
organic thiocyanates, phenolic biocide, alkylamines, diamines,
triamines, dithiocarbamates, 2-(decylthio)ethanamine and its
hydrochloride, triazine derivatives, oxazolidines and combinations
thereof present in the range of 1 to 5% by weight of the total
composition.
13. The method according to claim 1, wherein the emulsion further
comprises a chelating agent selected from the group consisting of
ethylenediamine tetraacetic acid, hydroxyethylenediamine triacetic
acid, nitriolotriacetic acid, citric acid, acetylacetone,
porphyrin, catechol, dithiolene phosphonic acids and their salts,
polyphosphates, phosphate esters, nonpolymeric phosphonates,
aminophosphonates, polyphosphonates phosphino polymers,
polyphosphinates, polycarboxylates, polysulfonates and combinations
thereof present in an amount of 1 to 10% by weight of the total
composition.
14. The method according to claim 1, wherein the emulsion further
comprises a corrosion inhibitor selected from the group consisting
of phosphate esters, amine salts of carboxylic acid, amine salts of
polycarboxylic acid, quaternary ammonium salts, quaternary imminium
salts, amidoamines, imidazolines, amides, polyhydrxy amines,
polyhydroxy amides, ethoxylated amines, ethoxylated amides,
polyaminoacides and combinations thereof present in the range of 1
to 5% by weight of the total composition.
15. The method according to claim 1, wherein the emulsion further
comprises an acid selected from the group consisting of gluconic
acid, lactic acid, methanesulfonic acids, urea hydrochloride,
acetic acid, formic acid, citric acid, carboxylic acids with linear
or branched alkyl groups and number of carbon atoms in the alkyl
group from about 3-18, hydrochloric acid, hydrofluoric acid,
hydrobromic acid, phosphoric acid, sulfuric acid, nitric acid,
boric acid and combinations thereof present in the range of 5 to
10% by weight of the total composition.
16. The method according to claim 1, wherein the emulsion further
comprises a flocculant selected from the group consisting of
iron(III) salts, zinc(II) salts, aluminum(III) salts
diallyldimethylammonium chloride polymers, acrylamide-based
polymers, acrylate-based polymers, polyalkyleneimines,
polyalkanoamines, polyvinylammonium chloride, polyallylammonium
chloride, branched polyvinylimidazoline acid salts,
polysaccharides, chitosan, condensed tannins, dithiocarbamates,
hydrolyzed polyacrylamide-grafted xanthan gum,
poly-.gamma.-glutamic acid, and polyaspartic acid and combinations
thereof present in the range of 1 to 10% by weight of the total
composition.
17. The method according to claim 1, wherein the emulsion has a
surfactant/cosurfactant ratio in the range of 1/10 to 20/1.
18. The method according to claim 2, wherein the oil phase is
selected from the group consisting of terpenes, aromatic
hydrocarbons, glycols, esters, fatty acid ester, fatty ester,
glycol ethers, mineral oil, paraffin oil, plant-based oil, diesel,
petroleum distillates and combinations thereof.
19. The method according to claim 2, wherein the emulsion further
comprises an oxidizing biocide selected from the group consisting
of chlorine/hypochlorite or bromide/hypochlorite, hypochlorite
salts, hypobromite salts, stabilized bromine chloride, hydroxyl
radicals, chloramines, chlorine dioxide, chloroisocyanurates,
halogen-containing hydantoins, hydrogen peroxide, hydrogen
peracetic acid and combinations thereof present in the range of 1
to 5% by weight of the total composition.
20. The method according to claim 2, wherein the emulsion further
comprises a non-oxidizing biocide selected from the group
consisting of aldehyde biocides, quaternary phosphonium compounds,
quaternary ammonium surfactants, cationic polymers, organic
bromides, metronidazole, isothiazoles, isothiazolinones, thiones,
organic thiocyanates, phenolic biocide, alkylamines, diamines,
triamines, dithiocarbamates, 2-(decylthio)ethanamine and its
hydrochloride, triazine derivatives, oxazolidines and combinations
thereof present in the range of 1 to 5% by weight of the total
composition.
21. The method according to claim 2, wherein the emulsion further
comprises a chelating agent selected from the group consisting of
ethylenediamine tetraacetic acid, hydroxyethylenediamine triacetic
acid, nitriolotriacetic acid, citric acid, acetylacetone,
porphyrin, catechol, dithiolene phosphonic acids and their salts,
polyphosphates, phosphate esters, nonpolymeric phosphonates,
aminophosphonates, polyphosphonates phosphino polymers,
polyphosphinates, polycarboxylates, polysulfonates and combinations
thereof present in the range of 1 to 10% by weight of the total
composition.
22. The method according to claim 2, wherein the emulsion further
comprises a corrosion inhibitor selected from the group consisting
of phosphate esters, amine salts of carboxylic acid, amine salts of
polycarboxylic acid, quaternary ammonium salts, quaternary imminium
salts, amidoamines, imidazolines, amides, polyhydrxy amines,
polyhydroxy amides, ethoxylated amines, ethoxylated amides,
polyaminoacides and combinations thereof present in the range of 1
to 5% by weight of the total composition.
23. The method according to claim 2, wherein the emulsion further
comprises an acid selected from the group consisting of gluconic
acid, lactic acid, methanesulfonic acids, urea hydrochloride,
acetic acid, formic acid, citric acid, carboxylic acids with linear
or branched alkyl groups and number of carbon atoms in the alkyl
group from about 3-18, hydrochloric acid, hydrofluoric acid,
hydrobromic acid, phosphoric acid, sulfuric acid, nitric acid,
boric acid and combinations thereof present in the range of 5 to
10% by weight of the total composition.
24. The method according to claim 2, wherein the emulsion further
comprises a flocculant selected from the group consisting of
iron(III) salts, zinc(II) salts, aluminum(III) salts
diallyldimethylammonium chloride polymers, acrylamide-based
polymers, acrylate-based polymers, polyalkyleneimines, polyalkano
amines, polyvinylammonium chloride, polyallylammonium chloride,
branched polyvinylimidazoline acid salts, polysaccharides,
chitosan, condensed tannins, dithiocarbamates, hydrolyzed
polyacrylamide-grafted xanthan gum, poly-.gamma.-glutamic acid, and
polyaspartic acid and combinations thereof present in the range of
1 to 10% by weight of the total composition.
25. The method according to claim 2, wherein the emulsion has a
surfactant/cosurfactant ratio in the range of 1/10 to 20/1.
Description
FIELD OF INVENTION
[0001] The present invention relates a method of recovering oil
residue from oil sludge. In more detail, the disclosed method
employs an emulsion composition together with or without a liquid
carrier to recover the oil residue from solid or semi-solid object
such as in the crude oil sludge.
BACKGROUND OF THE INVENTION
[0002] Crude oil pumped out from wells is normally directed to
tanks for temporary storage before it is transported to refinery or
manufacturing purposes. Regular examination has to be performed
onto the crude oil storage tank to avoid accidental spill caused by
the tank leakage. However, quiescent state of the crude oil in the
storage tank prompts settlement of heavier fraction at the bottom
of the tank forming a sludge layer thereof. The sludge mainly
presented in a form of stable emulsion consists of long chain
paraffin, asphaltenes, inorganics and water. Sludge layer must be
removed from the tank before proper inspection can be performed.
Apart from that, the formed sludge layer also reduces storage
capacity of the tank and interfere connection in between the tank
to the refinery. It has been reported as well sludge accumulation
interrupts operation of floating roof of the storage tank
especially when the crude oil level is low in the tank. Considering
problems can be initiated by the presence of sludge layer in the
tank, effort has been put up to devise better ways to remove the
sludge layer. Still, the process is very costly and time-consuming
even after years of research.
[0003] It is important to be noted that sludge removal process
generally includes as well treatments such as separation and oil
recovery from the sludge prior to disposal of the sludge. Discharge
of improperly treated sludge can inflict great damage to the
environment. Since sludge is adherent in a solid or semi-solid
form, it is impossible to be channeled out from the tank via
pressure pump. Physically removing the sludge using machines or
human force is the most common applied approach that, sometimes, it
may be assisted by melting the sludge using heated medium like
steam. For example, Japanese patent application no. 8310589 and
International patent application no. 03002275 disclose specially
designed system for removing sludge physically from the tank. Such
approach may be, able to clean the tank, while the process is
time-consuming and labor-intensive. Even cleaning a single tank, it
takes days to complete. Further, post treatment after removing the
sludge physically, like centrifugation or filtration, always fails
to clean all the oil residues off solid particles in the sludge and
it is unlikely to dispose the sludge without polluting the
surrounding environment.
[0004] Beside physical removal, re-suspending the sludge into an
oil fraction is another option to reduce depth of the sludge inside
the tank. Preferably, the oil fraction is introduced on top of the
sludge under high pressure, while preheating or vortex may be
applied to accelerate dissolution of the sludge back into the crude
oil. For example, U.S. published patent 2008/0047871 and
International Patent Application 2010019548 respectively describe
sludge removal using high solvent power (HSP) crude oil and
atmospheric residue fraction of high solvency dispersive power
crude oil. Other U.S. Pat. Nos. 4,945,933, 5,019,016 and 5,460,331
disclose different apparatus equipped with a circulator coupled to
rotatable nozzles to create jet flow for dispersing sludge in crude
oil tank. Though re-suspension or re-dispersion work well in
discharging the sludge out from the tank, the discharged sludge of
these patents may eventually deposit somewhere in the subsequent
downstream processes and further treatment is needed to extract the
oil before dumping the sludge. In view of this, U.S. published
patent 2009/0173363 proposes deployment of filtration means to
remove the solid particles along pumping out the crude oil
suspension from the tank to avoid re-deposition of the sludge. At
least two filtering means are disposed in the disclosed system to
facilitate frequent filter exchange. Still, it is impossible to
achieve near complete extraction of oil residue from the sludge
through centrifuge or cyclone. While decomposing the sludge using
biological agent is described in U.S. Pat. No. 6,069,002, the
process requires a prolonged period in order to fully break down
the sludge.
[0005] Some of the above mentioned approaches may have achieved
significant results in sludge removal. Yet these approaches are far
from cost and energy efficient. Ideally, the process or the
composition used in sludge removal shall be able to drive recovery
of the entrapped oil residues from the solid particle in a
spontaneous mechanism without much machinery or energy
intervention.
SUMMARY OF THE INVENTION
[0006] The present invention provides a method of recovering oil
residue, particularly crude oil residue, entrapped to solid or
semi-solid objects, such as crude oil sludge accumulated in the
crude oil storage tank. In more specific, the present invention
employs a unique water-in-oil emulsion in the disclosed method to
attain effective separation and recovering of the crude oil reside
in the oil sludge.
[0007] Also another object is to offer energy and cost efficient
method for recovering crude oil from the contaminated solid and
semi-solid objects. Through performing the disclosed method in a
preferred condition with the unique emulsion composition, less
mechanical or energy intervention is needed to achieve significant
oil recovery compared to conventional approaches.
[0008] Moreover, the liquid phase obtained from the recovered oil
sludge using the disclosed method can be reused for several times
without apparent decrease in efficiency. Thus, the disclosed method
is able to reuse and recycle the liquid phase of the treated oil
sludge for subsequent oil sludge treatment.
[0009] Still another object of the present invention is to offer a
method to substantially clean crude oil contaminated soil with
ease. The contaminated soil may be resulted from accidental oil
spillage.
[0010] Further object of the present invention is to disclose a
method for cleaning sludge, especially crude oil sludge, deposited
in a storage tank. Through the nano-emulsion in the described
composition, the separation of the oil residues from the solid
particles is spontaneous thus reducing viscosity of the sludge to
facilitate subsequent removal of the sludge from the tank
later.
[0011] At least one of the preceding objects is met, in whole or in
part, by the present invention, in which one of the embodiments of
the present invention includes a method of treating a first batch
of oil sludge containing entrapped oil residues comprising the
steps of bringing into contact the first batch of oil sludge to a
liquid composition of an emulsion with or without a carrier,
wherein the emulsion comprises an alkylpolyglucoside surfactant in
2 to 40% by weight of total composition; a co-surfactant in 1 to
30% by weight of total composition selected from the group
consisting of C3 to C18 alcohols, C3 to C18 alkyl lactates,
lecithins, C3 to C18 fatty acids and any mixtures thereof; an oil
phase in 15 to 90% by weight of total composition; and an aqueous
phase in 0.5 to 20% by weight of total composition; homogenizing
the liquid composition with the first batch of oil sludge; and
fluidizing the oil sludge that the oil residues are substantially
dissociated from the solid or semi-solid object forming a liquid
phase including the liquid composition and the separated oil.
Preferably, the surfactant/cosurfactant ratio ranges from 1/10 to
20/1.
[0012] Preferably, the liquid composition and the oil sludge are
heated to a preferred temperature during the homogenizing step.
[0013] In another embodiment, the method may further comprise the
step of recycling the liquid phase or portion of the liquid phase
to a second batch of oil sludge to separate oil residue from the
solid objects in the second batch of oil sludge.
[0014] In another embodiment, the disclosed method involves
additional step of continuously removing the separated solid
objects from the liquid phase and/or adding new volume of oil
sludge into the liquid phase.
[0015] Preferably, the emulsion has a concentration of at least
0.01 to 10% by weight of the total liquid composition upon using
carrier, while the liquid composition and the oil sludge are in a
ratio of 1-10:20 by weight percentage. More preferably, the carrier
is light crude oil, paraffin oil, diesel, mineral oil, kerosene,
glycols, liquid hydrocarbons with viscosity less than 5000 cps at
25.degree. C., water, salt water or brine.
[0016] According to one preferred embodiment, the emulsion further
comprises a pour point depressant and/or wax inhibitors selected
from the group consisting of ethylene/alkene copolymers,
ethylene/vinyl acetate copolymers, ethylene acrylonitrile
copolymers, acrylate ester polymers, methacrylate ester polymers,
maleic copolymers, alkyl phenol-formaldehyde resins,
hexatriethanolamine oleate esters, polyolefin or any combination
thereof in 5 to 40% by weight of total composition.
[0017] Still, in another embodiment, the emulsion used in the
present method further comprises a chelating agent selected from
the group consisting of any one of combination of ethylenediamine
tetraacetic acid, hydroxyethylenediamine triacetic acid,
nitriolotriacetic acid, citric acid, acetylacetone, porphyrin,
catechol, dithiolene phosphonic acids and their salts,
polyphosphates, phosphate esters, nonpolymeric phosphonates,
aminophosphonates, polyphosphonates phosphino polymers,
polyphosphinates, polycarboxylates, and polysulfonates in 1 to 10%
by weight of total composition.
[0018] Still, in another embodiment, the emulsion further comprises
a corrosion inhibitor selected from the group consisting of any one
or combination of phosphate esters, amine salts of carboxylic acid,
amine salts of polycarboxylic acid, quaternary ammonium salts,
quaternary imminium salts, amidoamines, imidazolines, amides,
polyhydrxy amines, polyhydroxy amides, ethoxylated amines,
ethoxylated amides, and polyaminoacides in 1 to 5% by weight of
total composition.
[0019] Further a flocculant selected from the group consisting of
any one or combination iron(III) salts, zinc(II) salts,
aluminum(III) salts diallyldimethylammonium chloride polymers,
acrylamide-based polymers, acrylate-based polymers,
polyalkyleneimines, polyalkanoamines, polyvinylammonium chloride,
polyallylammonium chloride, branched polyvinylimidazoline acid
salts, polysaccharides, chitosan, condensed tannins,
dithiocarbamates, hydrolyzed polyacrylamide-grafted xanthan gum,
poly-.gamma.-glutamic acid, and polyaspartic acid in 1 to 10% by
weight of total composition can be incorporated in the emulsion
employed in the disclosed method.
DETAILED DESCRIPTION OF THE INVENTION
[0020] It is to be understood that the present invention may be
embodied in other specific forms and is not limited to the sole
embodiment described herein. However modification and equivalents
of the disclosed concepts such as those which readily occur to one
skilled in the art are intended to be included within the scope of
the claims which are appended thereto.
[0021] The term "sludge" used herein throughout the description
shall refer to thick, viscous hydrocarbons sometimes containing
water, sediment and/or residue that form after the aging of the
sedimentation. The term "oil" includes hydrocarbons, triglycerides;
esters, fatty alcohols and oil soluble silicones. Further, the oil
residue can be fossil-based, animal-based or plant-based oil.
[0022] The "nano-sized" emulsion used in the disclosed composition
preferably refers to droplets of the discontinuous phase in the
size not exceeding 200 nm.
[0023] The present invention is a method of treating a first batch
of oil sludge containing entrapped oil residues comprising the
steps of bringing into contact the first batch of oil sludge to a
liquid composition of an emulsion with or without a carrier,
wherein the emulsion comprises an alkylpolyglucoside surfactant in
2 to 40% by weight of total composition; a co-surfactant in 1 to
30% by weight of total composition selected from the group
consisting of C3 to C18 alcohols, C3 to C18 alkyl lactates,
lecithins, C3 to C18 fatty acids and any mixtures thereof; an oil
phase in 15 to 90% by weight of total composition; and an aqueous
phase in 0.5 to 20% by weight of total composition; homogenizing
the liquid composition with the first batch of oil sludge; and
fluidizing the oil sludge that the oil residues are substantially
dissociated from the solid object forming a liquid phase including
the liquid composition and the separated oil. Preferably, the
surfactant/cosurfactant in the emulsion has a ratio of 1/10 to
20/1.
[0024] Preferably, the oil sludge is in a solid or semi-solid phase
which can be crude oil sludge or crude oil contaminated soil. Voids
may be presented in the solid particles entrapping the oil residue,
therefore reducing mobility and flowability of the oil sludge
rendering removal of the sludge infeasible. With the aid of the
specially designed emulsion, the present invention is able to
re-suspend the crude oil residues into liquid phase or even
separate the crude oil residues from being entrapped to the solid
phase thereafter. More particularly, the emulsion used in the
described method is prepared in the form of nanoemulsion with
ultra-low interfacial tension, preferably in the form of Winsor
Type III emulsion or near Winsor Type III emulsion. The ultra-low
interfacial tension and the nano-sized water droplets in the
emulsion tend to adhere and spread through surface of a solid
object when the condition of use is right. Thus, the disclosed
method is able to displace the oil residue, especially crude oil
residue, from the surface of the solid objects for oil recovery and
sludge treatment. The oil phase of the emulsion composition serves
as a transportation medium for delivering the enclosed water
droplets into contact with the crude oil adhered on the surface of
the solid objects in the sludge. Owing to the nano-size and
ultra-low interfacial tension as well as presence of the oil phase,
the nano-sized water droplets can seep through the contacting
surface in between the crude oil and the solid object and instantly
wet this surface of the solid object. Once the surface of the solid
object in the sludge is water-wet or become hydrophilic, it
displaces or repels the crude oil from the solid surface.
[0025] This mechanism is thermodynamic driven and spontaneous
requiring minimal intervention. Displacement of the crude oil
residue or other oil residues from the surface of the solid objects
in the sludge, particularly sludge in the crude oil storage tank,
has tremendously soften the sludge and reduces viscosity thereby.
More preferably, the crude oil sludge is separated into two or
three major phases, namely the displaced oil phase on top, a
coalescent water layer at the middle and the settled solid
particles at the bottom. To be noted the emulsion containing-liquid
phase, which can be the displaced oil phase or coalescent water
phase or both, can be recycle for subsequent sludge treatment as
described in the below section. According to one preferred
embodiment, the oil phase is collected for refinery while solid
particles are disposed with or without further treatment. To bring
the liquid composition into contact with solid and/or semi-solid
phase at increased rate, mechanical agitation, mixing, flushing
and/or homogenizing are preferably implemented in the present
invention. Moreover, in sludge containing entrapped water droplets
in the form of emulsion, surfactants of the disclosed composition
results in the coalescent of the water droplets in the sludge
forming larger water aggregate that it further separates water from
the oil residue. Segregation of the water and solid particles in
the treated sludge hence improves flowability of the sludge and can
be channelled out of the tank
[0026] In conjunction with the use of the mentioned emulsion, the
disclosed method can recycle or reuse the liquid phase containing
both oil residue and the emulsion for treating the new volume of
oil sludge. The liquid phase mentioned herein specifically refers
to liquid portion or a flowable fraction acquired from the treated
first batch of oil sludge. Depending on the grade and types of oil
sludge treated, the liquid phase in the disclosed invention can
also refer to flowable fraction composed of a mixture of the solid
objects and oil residues as well as the emulsion besides pure
liquid fraction of oil residues and the emulsion. More
specifically, the disclosed method may additionally comprise the
step of recycling the liquid phase or portion of the liquid phase
to a second batch of oil sludge, wherein the second batch of oil
sludge containing entrapped oil residue; and homogenizing the
liquid phase or portion of the liquid phase to the second batch of
oil sludge to separate oil residue from the sludge. Prior to
recycling the liquid phase, treatment for separating the solid
objects out of the flowable fraction may be performed. Preferably,
the disclosed method pumps the crude oil through a solid-liquid
separator to segregate out solid particles, water and oil. The
separator can be centrifuge, cyclone, liquid-solid separator,
gravitational sedimentation separator, sedimentation pond or any
means of separation method that can displace high density solid
from oil and water.
[0027] In another embodiment, the disclosed method involves
additional step of continuously removing the substantially
separated solid objects from the liquid phase and/or adding new
volume of oil sludge into the liquid phase. More specifically, in a
continuous process for treating the oil sludge, part of the
separated and precipitated solid objects maybe removed from the
system for disposal or further treatment. Thus, fluidity of the
remaining oil sludge and liquid phase is significantly increased.
Further, in another embodiment, new volume of oil sludge may be
added into the system while the substantially separated solid
objects are being removed. This is another approach of the
disclosed method to recycle and reuse the liquid phase for oil
sludge treatment provided that, but not limited to, the newly added
volume of oil sludge at least limitedly flowable.
[0028] Moreover, it was found by the inventors of the disclosed
invention that the disclosed invention can be implemented with or
without the liquid carrier. In the absence of liquid carrier, much
higher volume of the emulsion formulation is required to fully
cover and suspend the crude oil sludge or the contaminated solid
objects that incurring higher operational cost. On the other hand,
the embodiment using the liquid carrier increases the contactable
surface area of the nanoemulsion for displacing the crude oil
residues and assist in separation or dissolution of the sludge. The
liquid carrier compatible with the disclosed invention can be an
aqueous based or hydrocarbon-based solvent. The hydrocarbon-based
solvent is light crude oil, diesel, mineral oil, kerosene, aromatic
hydrocarbons, glycols, or other liquid hydrocarbon with viscosity
less than 5000 cps at 25.degree. C. More preferably, the light
crude oil employed has API gravity higher than 31.degree. API or
870 kg/m.sup.3. The aqueous solvent can be water, salt water, or
brine. Relying on the types of liquid carrier used in the present
invention, the outcome of different disclosed embodiments of the
disclosed invention may be varied. For instance, aqueous liquid
carrier may have the crude oil residues accumulated on top of the
liquid carrier while the solid particles settled at the bottom of
the carrier facilitating complete cleaning of the crude oil sludge.
In contrast, using of light crude oil as carrier can have the crude
oil sludge re-suspended in an accelerated rate compared to the
aqueous liquid carrier while an additional separating step is
needed at the subsequent downstream process to segregate the solid
object and liquid phase. The separation step in the present
invention may be performed using centrifuge, cyclone, liquid-solid
separator, gravitational sedimentation or any other means of
separation.
[0029] Preferably, the disclosed method can be employed at various
mode of process. In one embodiment where the method is performed as
a continuous process, the disclosed method may further comprise the
step of introducing the liquid phase or portion of the liquid phase
to the solid or semi-solid phase to continue separating crude oil
from the solid or semi-solid phase. Specifically, the acquired
separated crude oil together with the liquid composition is
recycled back into the system to continue extracting the liquid oil
from the crude oil sludge or re-suspend (re-dispersed) the sludge.
Additional liquid composition may be injected, but not necessary;
into the recycled liquid phase especially volume of the crude oil
sludge to be removed or treated is large. Further, in the
embodiment where the disclosed process is a batch process, the
acquired separated liquid phase is channeled out from the tank
containing the crude oil sludge together with the re-suspended
sludge and treated with physical separation step as mentioned above
without reusing the separated crude oil obtained from the system.
Still in the embodiment of semi-batch process, the re-suspended
crude oil together with the liquid composition from a primary tank
is directed into at least one secondary tank containing a new batch
of semi-solid or solid phase to generate a secondary fraction of
liquid phase thereof, while the secondary liquid phase may be then
channeled back to the primary tank or the secondary tank upon user
preference for to continue the sludge removing process. In short,
the method includes extra step of introducing the liquid phase or
portion of the liquid phase to a secondary solid or semi-solid
phase to separate crude oil from the secondary solid or semi-solid
phase in this embodiment.
[0030] Additionally, the disclosed method in another embodiment may
further comprise the step of heating the liquid composition and
solid or semi-solid phase together during the homogenizing step.
Applying heat energy into the mixture of liquid composition and
solid or semi-solid phase expedite dissolution or extraction or
re-suspension of the crude oil sludge into forming the liquid
phase. Caution has to be taken when liquid hydrocarbon is used as
the carrier that the heating temperature shall be few degree below
the flash point of the carrier. In the case which aqueous-based
carrier is used, the mixture is preferably heated above 25.degree.
C.
[0031] Preferably, the oil phase of the disclosed invention is any
one or combination of terpenes, aromatic hydrocarbons, glycols,
esters, fatty acid ester, fatty ester, glycol ethers, mineral oil,
paraffin oil, plant-based oil, diesel, and petroleum distillates.
More preferably, the petroleum distillates have flash point higher
than 60.degree. C. To impart better biodegradability and to be
ecological friendly, terpenes such as d-limonene is preferably used
to constitute the oil phase of the disclosed invention. The
d-limonene can be acquired as plant extraction or being chemically
synthesized.
[0032] It is known in the art that asphaltene and paraffin are
other organic substances in the crude oil contribute to formation
of the sludge. Particularly, depositional effects of oil sludge in
storage tank and/or pipeline can largely attribute to presence of
asphaltenes in the oil, while paraffin are alkanes with long carbon
chain presented as solid mass in room temperature. These substances
tend to interact and entrap water molecules in the crude oil sludge
rendering low mobility to the sludge. In one embodiment of the
disclosed method, the liquid composition and the first batch of oil
sludge or the liquid phase and the second batch of oil sludge are
heated during the homogenizing step. The introduced heat prompts
dissolution of the paraffin into the emulsion used and renders the
oil sludge flowable. The disclosed method may heat the oil sludge
together with the liquid composition or the recycled liquid phase
to a temperature of, but not limited to, 40 to 70.degree. C. for
sufficiently melting the paraffin. To react more effectively for
removing crude oil sludge containing high amount of asphaltene
and/or paraffin, the disclosed method concurrently employs the
emulsion additionally added with a pour point depressant and/or wax
inhibitors in 5 to 20% by weight of total composition of emulsion.
The pour point depressant and/or wax inhibitors in this embodiment
react with the asphaltene and/or paraffin presented in the crude
oil sludge, preferably via agglomeration and/or flocculation. The
flocculated asphaltene and/or paraffin may be rid off from the
separated crude oil layer through filtration, while the
agglomerated particles are settled together with the solid
particles. Further, eliminating these organic substances from the
sludge also prevents potential interference caused towards the
overall performance of the disclosed nanoemulsion, especially
unwanted interaction with the water droplets in the nanoemulsion.
The pour point depressant and/or wax inhibitors can be any one or
combination ethylene/alkene copolymers, ethylene/vinyl acetate
copolymers, ethylene acrylonitrile copolymers, acrylate ester
polymers, methacrylate ester polymers, maleic copolymers, alkyl
phenol-formaldehyde resins, hexatriethanolamine oleate esters,
polyolefin or any combination thereof in 5 to 40% by weight of
total composition. Apart from that, a stablilizer may be needed in
the disclosed composition to stabilize the nanoemulsion in addition
of the pour point depressant and/or wax inhibitors. Preferably, the
stabilizer is any one of combination of dodecylbenzenesulfonic
acid, arylalkanesulfonates, sulfosuccinate esters,
alkyldiphenylether sulfonates, alkyldiphenylether disulfonates
alkylnaphthalenesulfonates, naphthalenesulfonic acid-formaldehyde
condensates in 1 to 10% by weight of total composition.
[0033] Further, a biocide in 1 to 5% by weight of total composition
is added in one embodiment of the disclosed composition. Using of
biodegradable components subjects the disclosed composition to
potential fermentation from biological agent such as bacteria and
fungus. The biocide prohibits growth of biological agent and
prolongs shelf life of the disclosed composition. The biocide used
in the present invention can be of oxidizing biocides or
non-oxidizing biocides. For oxidizing biocide, it can be any one or
combination of chlorine/hypochlorite or bromide/hypochlorite,
hypochlorite salts, hypobromite salts, stabilized bromine chloride,
hydroxyl radicals, chloramines, chlorine dioxide,
chloroisocyanurates, halogen-containing hydantoins, hydrogen
peroxide and hydrogen peracetic acid in 1 to 5% by weight of total
composition. On the other hand, a non-oxidizing biocide can be
selected from the group consisting of any one or combination of
aldehyde biocides, quaternary phosphonium compounds, quaternary
ammonium surfactants, cationic polymers, organic bromides,
metronidazole, isothiazoles, isothiazolinones, thiones, organic
thiocyanates, phenolic biocide, alkylamines, diamines, triamines,
dithiocarbamates, 2-(decylthio)ethanamine and its hydrochloride,
triazine derivatives, and oxazolidines in 1 to 5% by weight of
total composition.
[0034] Pursuant to another preferred embodiment, the disclose
composition or emulsion of includes a corrosion inhibitor which can
ranged from 1 to 5% by weight of the total composition. Sudden
liquefying of the accumulated crude oil sludge is likely to release
previously entrapped oxidative agent into the storage tank. The
released oxidative agent may then progressively erode the metal
surface of the storage tank. The corroded surface possibly ruptures
upon filling of the crude oil and leads to leakage. Most of the
commercially available corrosion inhibitor is applicable in the
present invention. Yet, the corrosion inhibitors is more preferably
chosen from phosphate esters, amine salts of carboxylic acid, amine
salts of polycarboxylic acid, quaternary ammonium salts, quaternary
imminium salts, amidoamines, imidazolines, amides, polyhydrxy
amines, polyhydroxy amides, ethoxylated amines, ethoxylated amides,
polyaminoacides or any combination derived thereof.
[0035] Further, the disclosed method may use an emulsion
additionally containing an acid selected from the group consisting
of gluconic acid, lactic acid, methanesulfonic acids, urea
hydrochloride, acetic acid, formic acid, citric acid, carboxylic
acids with linear or branched alkyl groups and number of carbon
atoms in the alkyl group from about 3-18, hydrochloric acid,
hydrofluoric acid, hydrobromic acid, phosphoric acid, sulfuric
acid, nitric acid, and boric acid in 5 to 10% by weight of total
composition. The acid in the emulsion allows the disclosed method
to break down or digest wax content and solid scale in the oil
sludge. Presence of high wax content prompts the formation of
macro-emulsion in the oil sludge that it reduces flowability of the
oil sludge leading to clogging of the sludge in the tank or
pipeline. Besides, some of the weak acids may be used together with
its salts in the present invention to function as pH buffering
agent for stabilizing the formed nanoemulsion for treating other
types of oil sludge. Abrupt fluctuation of pH may lead to phase out
of the nanoemulsion and hamper the efficiency of the disclosed
method.
[0036] Owing to the fact that the collected oil residues from the
oil sludge will be eventually reprocessed for fuel production, it
is preferred the oil residues are concurrently pre-treated once it
is released from the oil sludge. For achieving such purpose, a
chelating agent preferably is incorporated into the emulsion as
well with a concentration of 1 to 10% by weight of total
composition to remove metal ion such as iron, vanadium, nickel and
copper in the oil residues. Removing at least fraction of the metal
ions from the collected oil residues through the disclosed
composition relieves the subsequent downstream process.
[0037] In another embodiment, the emulsion further comprises a
flocculant selected from the group consisting of any one or
combination iron(III) salts, zinc(II) salts, aluminum(III) salts
diallyldimethylammonium chloride polymers, acrylamide-based
polymers, acrylate-based polymers, polyalkyleneimines,
polyalkanoamines, polyvinylammonium chloride, polyallylammonium
chloride, branched polyvinylimidazoline acid salts,
polysaccharides, chitosan, condensed tannins, dithiocarbamates,
hydrolyzed polyacrylamide-grafted xanthan gum,
poly-.gamma.-glutamic acid, and polyaspartic acid in 1 to 10% by
weight of total composition.
[0038] The effective volume of the emulsion in the liquid
composition is preferably of 0.05 to 10% by weight of the total
liquid composition when carrier is used together, though higher
concentration can be used as well. Further, the effective volume of
the treating liquid composition and the oil sludge is in a ratio of
1-10:20 by weight percentage. Accordingly, the carrier can be light
crude oil, paraffin oil, diesel, mineral oil, kerosene, glycols,
and liquid hydrocarbons with viscosity less than 5000 cps at
25.degree. C., water, salt water or brine.
Example 1
[0039] The present invention presented in following examples are
water-in-oil nanoemulsion with oil-water interfacial tension lower
than 0.01 mN/m (measured at 25.degree. C. by KRUSS spinning drop
tensiometer; model SITE100). The mean particle size of the
nanoemulsion is smaller than 200 nm (measured at 25.degree. C. by
particle size analyzer; Malvern Zetasizer Nano ZS). The sludge
types listed in Table 1 were the samples used in testing various
embodiments of the present invention. Properties of each sludge
type were determined using the retort analysis.
TABLE-US-00001 TABLE 1 Properties of the sludge types Total "Total"
% Oil that Water Oil can be content Content Density Apprx.
extracted Initial from from Wax of Weight up to % Water Sludge
Retort Retort at Extracted of 900.degree. F. Content in Weight Test
Test 25 C. Oil Extracted in Sludge sludge Solids Sludge Color Form
Source (g) (g) (mL) (mL) (g/mL) Oil (g) (w/w %) (w/w %) (wt %) A
Black Dried Refinery 20 2 15 2 0.813 12.2 61.0 10.0 29.0 B Black
Dried Refinery 20 1.5 14.5 1.5 0.812 11.8 58.9 7.5 33.6 C Black Wet
Distilation 20 5 5 0.0 0.82 4.1 20.5 25.0 54.5 D Black Lumpy Crude
oil platform 20 1.5 16 1.5 0.823 13.2 65.8 7.5 26.7 E Black Lumpy
Crude oil platform 20 1.5 16 1.5 0.823 13.2 65.8 7.5 26.7 F Black
Wet & Crude oil platform 20 4 14 0.0 0.81 11.3 56.7 20.0 23.3
lumpy G Black Lumpy with Distillation 20 5.5 4 1.0 0.82 3.3 16.4
21.5 56.1 very strong smell H Yellow-to- Dried solid Contaminated
soil 20 11.5 2.5 0.0 0.82 2.1 10.3 57.5 32.3 orange I Black to
Lumpy Crude oil platform 20 2.836 10.246 0 0.826 8.5 42.3 14.2 43.5
dark chocolate
[0040] The present invention was tested with 2 kinds of crude oil
tank bottom sludges (Sludge A and Sludge B) containing around 10
and 7.5 w/w % of water, respectively. The test was conducted at
room temperature, 25.degree. C. The 200 g of original sludge has
been prepared in 250 glass mL beaker according to the composition
in the table 2 below. Light crude having density of 30.degree. API
was used as carrier or diluent. The mixture was stirred for 15
minutes prior to measuring the viscosity at 25.degree. C. using
Brookfield viscometer model LVT and pour point using ASTM D97
Method. It was found that in case of the dried sludge, the liquid
carrier was needed for dispersing the present invention through the
sludge mixture.
[0041] Adding in small volume of light crude oil carrier (such as
10-20 w/w %) without the present invention into the sludge was not
sufficient to achieve low viscosity at 25.degree. C. The pour point
was still higher than 45.degree. C. Moreover, the solid such as
sand particles in the sludge could not be separated out. However,
if the 1000 ppm of the present invention (only 0.1 w/w %) was added
to sludge together with the light crude oil carrier (.about.10-20
w/w %), the viscosity of the sludge mixture was significantly
reduced to lower than 5000 cP and the pour point was reduced to
lower than 25.degree. C. The sludge was able to flow at normal room
temperature. Sand and water were able to be separated out
spontaneously by the action of the disclosed composition of the
present invention. On the other hand, if sufficient amount of light
crude oil carrier (such as 90 w/w %) was added to the sludge, the
sludge would be flowable. Yet only large sand and solid particles
settled down, while the fine particles of sand potentially
suspended in the sludge/crude oil mixture. This mixture still
requires doping by the present invention in order to completely
separate the sand out from the sludge/crude oil mixture.
TABLE-US-00002 TABLE 2 Effectiveness of the present invention on
viscosity and pour point reduction of the sludge from crude oil
tank bottom The present Oil phase in invention Pour Sludge Carrier
the present (w/w % in Viscosity at 25.degree. C. Point Solid Sample
No. (w/w %) Carrier (w/w %) invention sludge) (cP) (.degree. C.)
Sedimentation Sludge A A1 100 No 0 NA 0 Dried/cannot >45 No
measure A2 90 Light Crud Oil 10 NA 0 21,200 >45 No A3 90 Light
Crud Oil 9.9 Natural oil 0.1 2,100 15 Yes A4 80 Light Crud Oil 20
NA 0 18,700 >45 No A5 80 Light Crud Oil 19.9 Natural oil 0.1
1100 9 Yes A6 10 Light Crud Oil 90 NA 0 <100 <6 Slightly A7
10 Light Crud Oil 90 Natural oil 0.1 <100 <6 Yes Sludge B B1
100 No 0 NA 0 Dried/cannot >45 No measure B2 80 Light Crud Oil
20 NA 0 48,600 >45 No B3 80 Light Crud Oil 19.9 Glycol oil 0.1
2,900 21 Yes
Example 2
[0042] In this example, sludge C containing much higher solid
content was treated by addition of toluene as the carrier and the
present invention containing natural oil. The result shows that
addition of toluene as the carrier reduced the viscosity and pour
point of the sludge at the beginning (Sample No. C2 and C3). Using
larger amount of toluene helped in reducing the sludge viscosity.
However, the viscosity and pour point could not be maintained at
low level over time. Over time, the viscosity and pour point
increased to more than 25,000 cP and 45 after 24 hours,
respectively. Moreover, the solid sedimentation such as sand was
not observed in the experiment.
[0043] After adding in small amount of the present invention into
the sludge/toluene mixture (Sample No. C4-C5), it was found that
the viscosity of the sludge/toluene mixture was significantly
reduced. Adding larger amount of the present invention promotes
decrease in the viscosity of the sludge/toluene mixture as well.
The viscosity after the treatment using present invention could be
as low as 300 cP. Pour point of the mixture after treatment
decreased from higher than 45.degree. C. to lower than 15.degree.
C. No changes were observed in viscosity of all tested samples in
the presence of the present invention even after 24 hours.
Additionally, sand sedimentation was clearly observed after
addition of the present invention. Further, applying the present
invention without carrier (sample no. C6) also showed significant
reduction in pour point and viscosity of the sludge as well as
promoting solid separation from the sludge. The results are shown
in Table 3 below.
TABLE-US-00003 TABLE 3 Viscosity at Oil phase in The present
Viscosity 25.degree. C. Pour Point Sample Sludge Carrier the
present invention at 25.degree. C. Pour Point after 24 hrs after 24
hrs Solid No. (gram) Carrier (gram) invention (gram) (cP) (.degree.
C.) (cP) (.degree. C.) Sedimentation Sludge C C1 100 No 0 NA 0
>25,000 >45 >25,000 >45 No C2 100 Toluene 30 NA 0 3,000
15 >25,000 >45 No C3 100 Toluene 50 NA 0 2,100 15 >25,000
>45 No C4 100 Toluene 30 Natural oil 0.1 1,800 <15 3,000
<15 Yes C5 100 Toluene 30 Natural oil 1 800 <15 800 <15
Yes C6 100 No 0 Natural oil 50 300 <15 300 <15 Yes
Example 3
[0044] Different from example 2, sludge D with higher oil content
and low water and solid content was treated. Light crude having
density of 30.degree. API was used as carrier or diluent, while
various embodiment of the present invention employing different
kinds of oil phase such as natural oil, aromatics, and paraffin oil
were used. It was found that the addition of carrier without the
present invention could only reduce the viscosity of the sludge at
the initial stage, but the viscosity gradually increased over time
resulting in viscosity higher than 25,000 cP after 24 hours.
Separation of solid from liquid phase was not observed.
[0045] Using different embodiments of the present invention
constituted from different kinds of oil phase in the sludge/carrier
mixture shows different efficiency to lower the viscosity of the
sludge. The embodiment natural oil shows relatively higher
efficiency in reducing viscosity of the sludge than the other
embodiments containing aromatics and paraffin oil. Significant pour
point reduction, to lower than 9.degree. C., was observed after
addition of the present invention into the sludge. The sand
settlement at the bottom was found in all cases treated with the
present invention. The viscosity of the mixture remained unchanged
even after 24 hours. The results are shown in Table 4 below.
TABLE-US-00004 TABLE 4 Oil The Viscosity at Pour Point Pour Point
phase in present Viscosity 25.degree. C. after after Sample Sludge
Carrier present invention at 25.degree. C. Pour Point after 24 hrs
24 hrs 3 month Solid No. (gram) Carrier (gram) invention (gram)
(cP) (.degree. C.) (cP) (.degree. C.) (.degree. C.) Sedimentation
Sludge D D1 200 Light Crud Oil 20 NA 0 >25,000 39 >25,000 39
No data No D2 200 Light Crud Oil 40 NA 0 15,000 24 >25,000 33 No
data No D3 200 Light Crud Oil 20 Natural oil 0.5 8,000 15 11,000 21
No data Yes D4 200 Light Crud Oil 20 Natural oil 1 7,500 <9
6,000 <9 <9 Yes D5 200 Light Crud Oil 40 Natural oil 1 5,000
<9 6,000 <9 <9 Yes D6 200 Light Crud Oil 40 Natural oil 5
300 <9 330 <9 <9 Yes D7 200 Light Crud Oil 40 Aromatic 1
7,000 <9 7,000 <9 <9 Yes D8 200 Light Crud Oil 40
Paraffins 1 6,500 <9 7,000 <9 <9 Yes
Example 4
[0046] This experiment was an up-scale test for investigating the
impact of the present invention reacting on sludge of much larger
volume in the crude oil tank. Sludge E was used for the test. The
original quantity of the sludge for this up-scale test is 200 kg.
Light crude having density of 30.degree. API was used as carrier or
diluent. It was found that introduction of the present invention is
able to reduce viscosity and pour point of the sludge. The sand
settlement at the bottom only observed in test sample treated with
the present invention. The results are shown in Table 5 below.
TABLE-US-00005 TABLE 5 Pour Oil Viscosity at Point phase in The
present Viscosity Pour 25.degree. C. after Sample Sludge Carrier
present invention at 25.degree. C. Point after 24 hrs 24 hrs Solid
No. (kilogram) Carrier (kilogram) invention (kilogram) (cP)
(.degree. C.) (cP) (.degree. C.) Sedimentation Sludge E E1 100
Light Crud Oil 20 NA 0 >25,000 39 >25,000 39 No E2 100 Light
Crud Oil 20 Natural oil 0.5 5,000 <9 5,000 <9 Yes E3 100
Light Crud Oil 20 Natural oil 1 2,500 <9 2,500 <9 Yes
Example 5
[0047] This experiment was performed to test on the effectiveness
of the present invention when being used together with water as the
carrier. Sludge F was used for this test. It was observed that
introduction of the present invention was able to reduce the
viscosity and pour point of the sludge. The sand settlement at the
bottom was only observed in test sample treated with the present
invention. The results are shown in Table 6 below.
TABLE-US-00006 TABLE 6 Oil The Viscosity at phase in present
Viscosity at 25.degree. C. Pour Point Sludge Carrier present
invention 25.degree. C. Pour Point after 24 hrs after 24 hrs Solid
Sample No. (gram) Carrier (gram) invention (gram) (cP) (.degree.
C.) (cP) (.degree. C.) Sedimentation Sludge F F1 100 Water 50 NA 0
>25,000 >39 >25,000 >39 No F2 100 Water 50 Natural oil
1 5,000 <9 5,000 <9 Yes
Example 6
[0048] This experiment test on the effectiveness of the present
invention upon using different carriers namely water, mineral oil
and diesel oil, Sludge G was used. It was observed that the present
invention works well in different carriers. Test sample using water
as the carrier is slightly less effective than using mineral oil
and diesel oil as carrier in reducing viscosity of the sludge. The
sand settlement was observed in all test samples. The results are
shown in Table 7 below.
TABLE-US-00007 TABLE 7 Viscosity The at 25.degree. C. Pour Point
Oil phase in present Viscosity after after Sludge Carrier present
invention at 25.degree. C. Pour Point 24 hrs 24 hrs Solid Sample
No. (gram) Carrier (gram) invention (gram) (cP) (.degree. C.) (cP)
(.degree. C.) Sedimentation Sludge G G1 15 Water 1.5 NA 0
>25,000 >39 >25,000 >39 No G2 15 Water 1.5 Natural oil
0.15 1,000 No data 800 No data Yes G3 15 Water 2.5 Natural oil 0.15
800 No data 800 No data Yes G4 15 Mineral oil 0.75 Mineral oil 0.15
<800 No data <800 No data Yes G5 15 Diesel 0.75 Diesel 0.15
<800 No data <800 No data Yes
Example 7
[0049] Efficiency of the present invention for treating sludge
containing high water content (>50 w/w %) and low oil content
(.about.10 w/w %) was investigated in this experiment. Sludge H was
used and two different carriers tested were water and toluene. The
present invention together with water as the carrier show better
effectiveness in reducing viscosity of the sludge. Solid
sedimentation was clearly observed for test sample H1 only.
TABLE-US-00008 TABLE 8 Oil phase in The present Viscosity at Sludge
Carrier present invention 25.degree. C. Solid Sample No. (gram)
Carrier (gram) invention (gram) (cP) Sedimentation Sludge H H1 15
Water 15 Natural oil 0.15 1,200 Yes H2 15 Toluene 15 Natural oil
0.15 Not flowing No
Example 8
[0050] The impact of different kind of oil phase (natural oil,
diesel oil, sarapar oil) was investigated in this experiment while
water was selected as carrier. The sludge used in this example was
sludge I with higher water content. The results showed in Table 9
indicate that different kind of oil phase functioned well in
aqueous carrier in reducing the viscosity of the sludge, to lower
than 100 cP. Solid was separated from the sludge for all cases.
TABLE-US-00009 TABLE 9 Oil phase in The present Viscosity Sludge
Carrier present invention at 25.degree. C. Solid Sample No. (gram)
Carrier (gram) invention (gram) (cP) Sedimentation Sludge I I1 15
Water 15 Natural oil 0.75 <100 Yes I2 15 Water 15 Diesel 0.75
<100 Yes I3 15 Water 15 Sarapar 147 0.75 <100 Yes
Example 9
[0051] This example aims to compare the performance of the present
invention with and without using the carrier. In one sample, light
crude having density of 30.degree. API was used as carrier for
comparison. Sludge A was used for the test. It was found that using
the present invention solely without carrier still worked
effectively on sludge type A. Solid sedimentation was observed only
in experiments without using carrier. The test results are shown in
Table 10 below.
TABLE-US-00010 TABLE 10 The present Viscosity at Oil phase in
invention 25.degree. C. Sludge Carrier present (w/w % in Viscosity
at 25.degree. C. Pour Point after 24 hrs Solid Sample No. (w/w %)
Carrier (w/w %) invention total mixture) (cP) (.degree. C.) (cP)
Sedimentation Sludge A A4 80 Light Crud Oil 20 NA 0 18,700 >45
>25000 No A8 80 No 0 Natural oil 20 1,300 <15 1300 Yes A9 90
No 0 Natural oil 10 2,500 <15 2500 Yes
Example 10
[0052] This example aims to investigate the effectiveness of the
present invention at very low concentration (approximately nearly
100 ppm or 0.01 w/w % in sludge) with the presence of the carrier.
Light crude having density of 30.degree. API was used as carrier
for comparison. 5% of the carrier was used for the study. Sludge A
was used for the test. It was found that the present invention at
very low concentration still worked effectively on sludge type A in
the presence of carrier to reduce the viscosity below 5000 cP
(pumpable condition) and pour point of the sludge as well as
promoting the solid particle sedimentation.
TABLE-US-00011 TABLE 11 The present Viscosity at Oil phase in
invention 25.degree. C. Sludge Carrier present (w/w % in Viscosity
at 25.degree. C. Pour Point after 24 hrs Solid Sample No. (w/w %)
Carrier (w/w %) invention total mixture) (cP) (.degree. C.) (cP)
Sedimentation Sludge A A10 95 Light Crud Oil 5 Natural oil 0
>25000 >45 >25000 No A11 94.99 Light Crud Oil 5 Natural
oil 0.01 3,400 <15 3,400 Yes
[0053] The present disclosure includes as contained in the appended
claims, as well as that of the foregoing description. Although this
invention has been described in its preferred form with a degree of
particularity, it is understood that the present disclosure of the
preferred form has been made only by way of example and that
numerous changes in the details of construction and the combination
and arrangements of parts may be resorted to without departing from
the scope of the invention.
* * * * *